Today, Martin Luther is known as the man who stood against popes and emperors in defense of the gospel. What drove this lone German monk to defy the Roman Catholic Church? It wasn't arrogance or ignorance. Luther knew what it meant to live in the darkness of unresolved guilt. Once he discovered that his acceptance before God is a gift received by faith alone in the merits of Christ alone, Luther was set free, and he would not rest until the light of this truth went out to the world. In this book, Dr. R.C. Sproul guides us through several crisis moments in the life of Martin Luther that led to his recovery of the gospel revealed in Scripture. Justification by faith alone was a liberating truth for Luther and the other Protestant Reformers, and it is good news for us to cherish today.